Catecholamines inhibit leukotriene formation and decrease leukotriene/prostaglandin ratio.
Adrenaline, noradrenaline, isoprenaline, and to a lesser extent dopamine inhibit the release of leukotriene (LT) B2 from calcium ionophore-stimulated human polymorphonuclear leukocytes, while the release of prostaglandin (PG) E2 is proportionally elevated. The inactivity of salbutamol, a noncatechol adrenergic beta 2-receptor agonist, and the inability of propranolol to antagonize the effects of adrenaline, suggest the mediation through beta-receptor independent mechanisms. Neither are alpha-1-receptors involved, as prazosin, a specific antagonist, fails to inhibit the reaction. As the principles for biochemical regulation of LT- and PG-production are met by catecholamines in several tissues, the mechanism is considered to be of general physiological importance. Catecholamines may function as coenzymes/antioxidants which, by altering the redox state of the enzyme iron or heme, decrease the LT/PG ratio thus protecting the organism against tissue anaphylaxis and other LT-related pathophysiology.